1. Field of the Invention
The present invention relates to a process for producing an ammonium aromatic sulfonate, especially ammonium styrenesulfonate or a polymer thereof.
2. Description of the Prior Art
It is known that alkali metal salts of p-styrenesulfonate can be industrially produced by the reaction of p-.beta.-haloethylbenzenesulfonic acid with an alkali metal hydroxide, i.e., ##STR1## wherein X represents Cl or Br and M represents an alkali metal. When such an alkali metal salt of p-styrenesulfonate is polymerized by radical polymerization, units having molecular weights corresponding to both oligomers and polymers are obtained.
It is also known to the present authors that ammonium p-styrenesulfonate or a polymer thereof can be produced from alkali metal p-styrenesulfonate or a polymer thereof by using an ion exchange resin. However, the process has many attendant disadvantages: a large size apparatus is required in the industrial process low concentrations are required for the operation; the ion exchange rate is low; troublesome absorption phenomena can be caused and the recovery of the ion exchange resin is complicated. Consequently, it would be most desirable to have a process for producing the corresponding ammonium salt of an alkali metal p-styrenesulfonate or a polymer thereof which is highly useful on an industrial scale.